The present invention relates to a wear-resistant coating, in particular an erosion-resistant coating, preferably for gas turbine components. In addition, the invention relates to a component having such a wear-resistant coating.
Components that are exposed to high fluidic loads such as gas turbine components are subject to wear due to oxidation, corrosion and erosion. Erosion is a wear process caused by solids entrained in the gas flow. To prolong the lifetime of components exposed to fluidic loads, wear-resistant coatings, also known as armoring, to protect the components from wear, especially erosion, corrosion and oxidation, are required.
European Patent EP 0 674 020 B1 describes a multilayered erosion-resistant coating for surfaces of substrates. The erosion-resistant coating disclosed there provides a wear-resistant coating consisting of several multilayer systems applied to the substrate to be coated. For example, in European Patent EP 0 674 020 B1, the multilayer systems that are applied in repeating layers are formed from two different layers, namely first a layer of a metallic material and secondly a layer of titanium diboride. Since the multilayer systems applied repeatedly to produce the erosion-resistant coating according to European Patent EP 0 674 020 B1 are formed of only two layers, alternating layers of metallic material and layers of titanium diboride are arranged in the erosion-resistant coating disclosed there.
European Patent EP 0 366 289 A1 discloses another erosion-resistant and corrosion-resistant coating for a substrate. According to European Patent EP 0 366 289 A1, the wear-resistant coating is formed from multiple multilayer systems applied repeatedly to the substrate to be coated, each multilayer system in turn consisting of two different layers, namely a metallic layer, e.g., made of titanium, and a ceramic layer, e.g., made of titanium nitride.
Another erosion-resistant and abrasion-resistant wear-preventing coating is known from European Patent EP 0 562 108 B1. The wear-resistant coating disclosed there is in turn formed from multiple multilayer systems applied repeatedly to a substrate to be coated. FIG. 4 in European Patent EP 0 562 108 B1 discloses a wear-resistant coating formed by several multilayer systems applied repeatedly, each multilayer system in turn consisting of four layers, namely a ductile layer of tungsten or a tungsten alloy and three hard layers, whereby the three hard layers differ with regard to the presence of an additional element.
Hence this background, the problem on which the present invention is based is to create a novel wear-resistant coating and a component having such a wear-resistant coating.
According to this invention, each of the multilayer systems applied repeatedly has at least four different layers. A first layer of each multilayer system facing the surface to be coated is formed by a metallic material adapted to the composition of the component surface that is to be coated. A second layer of each multilayer system applied to the first layer is formed by a metal alloy material adapted to the composition of the component surface to be coated. A third layer of each multilayer system applied to the second layer is formed by a gradated metal-ceramic material and a fourth layer of each multilayer system applied to the third layer is formed by a nanostructured ceramic material.
The inventive wear-resistant coating ensures very good erosion resistance and oxidation resistance and has an extremely low influence on the vibrational strength of the coated component. It is suitable in particular for coating complex components such as guide vanes, rotor blades, guide vane segments, rotor blade segments and integrally bladed rotors.
Several such multilayer systems are applied repeatedly to the surface of the component exposed to fluidic loads, with an adhesive layer preferably being applied between the surface of the component and the first multilayer system directly adjacent to the surface.
Preferred refinements of the present invention are derived from the following description. Exemplary embodiments of the present invention are explained in greater detail below with reference to the drawings, although they are not limited to these embodiments.